Routine testing circuit



- 3 1940- .1. B. RETALLACK 2,227,330

ROUTINE TESTING CIRCUIT Filed Aug. 18, 1959 I 18 Sheets-Sheet l INVENTORi151 RENAL/46W 19v ATTORNEY Dec. 31, 1940. J. B. RETALLACK 2,227,380

\ ROUTINE TESTING CIRCUIT Filed Aug. 18, 1959 1a Skiet's-Sheet 2' INK/ENTOR Jfifi/FTALLAGM A T TOR/V5 V 1940- J. B. RETALLACK 2,227,330

ROUTINE TESTING CIRCUIT Filed Aug. 18, 1939 18 Sheets-Sheet 3 INVENTOR-J.B. REFILL/16K A TTQRNE V Dec. 31, 1940.

J. B. RETALLACK ROUTINE TESTINQ CIRCUIT Filed Aug 18, 1959 1asheets-sheet 4 INVE RETALLACK 63 6M ATTORNEY M53; ROUTINE TESTINGCIRCUIT Filed Aug. 18, 1939 18 Sheets-Sheet 5 INVENTO JBRETALLACKAi'TORNEV Dec. 31, 1940.

.J. B. RETALLACK ROUTiNE TESTING CIRCUIT Filed Au 18, 1939 18Sheets-Sheet s mob kob

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ROUTINE TESTING CIRCUIT Filed Aug. 18, 1959 1a Sheets-Sheet 9 ATTORNE VDec. 31, 1940. RTALLACK 2,227,380

ROUTINE TESTING CIRCUIT Filed Aug. 18, 1939 18 Sheets-Sheet l0 INVENTORJ.B. RETALLACK A T TORNE Y FIG. /0

Dec. 31, 1940. RETALLACK 2,227,380

ROUTINE TESTING CIRCUIT Filed Aug. 18, 1939 18 Sheets-Sheet ll INVE-J.B. RE TALLACK aam ATTORNE Y FIG. ll

31, 1940- J. B. RETALLACK 2,227,330

ROUTINE TESTING CIRCUIT Filed Aug. 18, 1939 18 sheets-sheet 12 INVENTOR.18. RETALLACK A T TORNE V FIG. 12

Dec. 31, 1940. J. B. RETALLACK 2,227,330

ROUTINE TESTING CIRCUIT Filed Aug. 18, 1939 1s Sheets-Shet 1s SEA/DERSENOER lNl ENTOR J. 8. RE TALLACK ATTORNEY Dec. 31, 1940. J. B.RETALLACK 2,227,380

ROUTINE TESTING CIRCUIT Filed Aug. 18, 1939 18 Sheets-Sheet l4 INVENTORJ. 5'. RE TALLACK A T TORNE V Dec. 31, 1940. .1. B. RETALLACK 2,227,380

ROUTINE TESTING CIRCUIT Filed Aug. 18, 19559 18 Sheets-Sheet l5 IHHII ll1 ATTORNE V De 1940- r J. B. RETALLACK 2,227,330

ROUTINE TESTING CIRCUIT Filed Aug. 18, 1959 18 Sheets-Sheet 16 am E 8 2Q 3 i i U i -l INVENTOR J. 3?. RE MAL/ 36W Arrow/E Dec. 31, 1940. B,RETALL'A K 2,227,380

ROUTINE TESTING CIRCUIT Filed Aug. 18, 1959 18 Sheets-Sheet l7 IMVEN TORgzfiwmmmmv TTQHMEV J. B. RETALLACK ROUTINE TESTING CIRCUIT Dec. 31,1940.

Filed Alig. 18, 1959 CONN.

DIS TRIC T Sheets-Sheet l8 INVENTOR M "EMAA TTmm/LW I1. tented Dec. 31,1940 UNITED STATES PATENT OFFICE ROUTINE TESTING CIRCUIT ApplicationAugust 18, 1939, Serial No. 290.764

15 Claims. (Cl. 179-1752) This invention relates to automatic telephonesystems and has for its object to maintain the efficiency thereof byproviding test equipment which causes the automatic apparatus tofunction as in service and reacts thereto to detect faults in suchfunctions.

More specifically, originating telephonic connections in the cross-barsystem are extended through district junctors which control theconnection in the originating office. They vary in accordance with themanner in which calls are to be charged, being associable with differentcharging means and controlling the charging means in a variety of ways.

Testing systems have been designed heretofore for testing similarcircuits in th panel system. The present invention is concerned withtests particularly applicable to the cross-bar system.

In accordance with the present invention, the

test circuit is associated with the junctors to be tested over a set ofcross-bar switches and means is provided for progressively operating thecrosspoints of the switches, together with means for insuring therelease of one l'unctor before the next junctor is seized.

The district junctors maintain a busy condition as long as the junctorsare in use and in accordance with the present invention the test circuitmaintains a continuous test for this busy condition while testing otherfeatures of the iunctor, as well as testing for its absence beforestarting tests. In a similar manner, district junctors associable withlines having message registers, maintain a guarding condition on thecharging circuit except when the circuit is in use, and the test circuitalso makes a continuous test for this guarding condition.

Charge current must be applied for a minimum length of time in order toinsure the operation of the register or coin box. The test circuit ofthe present invention tests for a suflicient duration of charge currentand varies the action of the timing means in accordance with the type ofjunctor being tested.

These and other features of the invention will be more apparent from aconsideration of the following description in connection with theattached drawings, in which:

Figs. 14 to 17 show connection control equipment:

.Fig. 7 shows a coin type district;

Fig. 8 shows in diagrammatic form a coin control circuit; 5

Fig. 13 shows a schematic marker, sender and switches for connecting thejunctors therewith and with the test lines;

Fig. 18 shows a message rate type district, and Fig. 19 shows the mannerin which the other figures should be arranged. I

Briefly, the operation of the test circuit is as follows: In accordancewith the type of test to be made, one or more of the keys of Fig. 9 isoperated, each key representing a particular test. The start key is thenoperated, causing the switches i500, i600 and IMO to advance to selectthe first cross-bar junctor switch and the first level and the firsthorizontal position thereof. Thereupon, the cross-point leading to thefirst district junctor is closed. In general, the Junetor is given abusy test and if idle, is directed to a test line. Then the supervisoryrelays are tested and finally the charging equipment. The test classswitch 900 is then advanced to the next class of test and that test ismade on the same junctor. After the tests corresponding to all operatedkeys have been made, the switch IBM is advanced to release thecross-point and then further advanced to operate the next cross- 30point. After the ten cross-points in the first level have been used,switch l6l0'is advanced to release the select magnet of the first leveland is then stepped to the next position where it operates the selectmagnet of the second level, and switch IMO is reoperated to close thecross-points 01 that level in succession. When the last junctoraccessible through the first cross-bar switch is tested, switch I500 isadvanced to select another switch. K

As above indicated the keys of Fig. 9 determine the tests to be made andthe off-normal positions of switch 900 correspond thereto. The testswhich may be made, with the key and position of switch 900, are asfollows:

Position Test Local charge. Free call. Call to operator. Disconnect.Condenser test. Automatic release.

us. Tip party charge.

The tests made in positions I3 and I5 are applicable only to certaintypes of junctors and therefore these keys should not be operated alone.

Relays 3I3 to 326 are individual to the vari ous types of districtjunctors and are operated under the joint control of the group relay andthe level switch, cross-connections being provided to accommodate thetest circuit to the arrangement of the particular ofiice in which it isinstalled. Each relay has a corresponding lamp 300 to 3I2 which islighted to indicate the type of district junctor under test. For zoneand two party tests it is necessary'that the proper district class relaybe operated to permit the test to be made.

Switch 900 also controls the dial pulsing circuit by operating one ofthe relays I00, I I I, H2, or II3 to control the code transmitted, inorder to give the marker the proper indication.

For convenience, only two types of district junctors have been shown,namely, that of Fig. 18 which is arranged for use with two party lineshaving message rate local and overtime service but no zone service andthat of Fig. 7 which is arranged for use with lines equipped with coinboxes and is also arranged for collecting for overtime calls.

The district junctor of Fig. 18 is marked idle by battery on conductorI821 and holds the line switches by connecting ground to conductor I181and the district and office switches by connecting ground to conductorI328 under the control of the incoming supervisory relay I806. Theoutgoing supervisory relay I8II controls the charging by means of camsI820 and I82I and controls the automatic release by means ofinterrupters I825 and I826. During the establishment of a connection thejunctor is connected with a marker and relay I805 is operated to permita record to be made for controlling the charge. In the message ratedistrict the charge is made at the beginning of each conversationalperiod.

In the coin junctor of Fig. '1, relays 130, H9 and 129 have the samefunctions as relays I806, I8 and I805, respectively. In this junctor thecoin is collected near the termination of the conversational period.

Connection with district junctor An automatic test of all of thedistrict junctors in the cross-bar office is started by the operation ofthe start key I422. The operation of this key closes a circuit frombattery through the winding of relay I42I, right back contact of relayI420 to ground at the left contact of key I422. Relay I42I operates inthis circuit and extends this same ground over its left contact, leftback contact of relay I548 to the winding of relay I409 and battery.Relay I409 locks over its middle left front contact to ground over theleft contact of start key I422 and also prepares a holding circuit foritself under the control of relay I023 by which it is prevented fromreleasing prior to the completion of a test call. The operation of thestart key I422 also closes a circuit over the right back contact ofrelay I4I1 to the winding of relay HM and battery, in which circuitrelay I4I4 operates.

The district junctors are connected to the test circuit by means of thecross-points of cross-bar switches such as switch I100. In order tocontrol the successive closure of the various cross-points, and therebythe successive seizure of the district junctors, three control switchesI500, I600 and I6I0 are provided. At the beginning of the test theseswitches should be in normal position and the operation of relay I409advances these switches into position to control the selection of thefirst district junctor to be tested. To this end the operation of relayI409 closes three circuits, namely, from ground at its inner rightcontact to conductor I426 and thence in parallel over the normal contactof brush I502 to the back contact and winding of stepping magnet I501and battery; over the normal contact of brush I602 to the back contactand winding of magnet I605 and battery; over the normal contact of brushI6 I2 and the back contact and winding of magnet I6|6 and battery. Dueto the closure of these circuits, switches I500, I600 and I6I0 aresimultaneously stepped to their first working positions.

Switch I500 controls the selection of a group of district junctors bythe selection of a par ticular cross-bar switch having access to thatgroup of junctors. In its first off-normal position a circuit is closedfrom ground at the second right front contact of relay I409, conductorI428, brush I503 and its first off-normal contact, conductor I554, tothe winding of multicontact group relay I150 and battery. This relay isassociated with cross-bar switch I to which the first group of onehundred district junctor circuits are connected for test. In otherpositions of group switch I500 other group relays, such as relay I169,are operated, which relays are each associated with cross-bar switchesto which other groups of district junctor circuits are connected.

With relay I 150 operated, a circuit is closed from ground over thefirst off-normal contact of brush I6I3 to lamp I640 and battery and inparallel therewith over armature I of relay I150 to the winding ofselect magnet I and battery. The select magnet I120 operates, preparingthe first row of cross-points of switch I100. As an indication that thecross-points have been prepared, magnet I120 also closes its leftcontact, completing a circuit over armature I11I of relay I 150, windingof relay I606 and battery. Relay I606 operates, closing a circuit overits front contact and brush I603 in its first off-normal posi tion tolamp I620 and battery, and in parallel therewith over armature I112 ofrelay I150 to the winding of hold magnet I and battery. Magnet I130closes cross-point I140, thereby connecting the first district junctorcircuit which is shown in Fig. 18 to the test circuit in preparation fortest.

Magnet I 130 also connects ground over its front contact, armature I115of relay I150, conductor I116, winding of relay I408 to battery, as anindication that the cross-point has been closed. With relay I408operated, a circuit is closed from ground at the outer right frontcontact of relay I409, inner left back contact of relay I 4I5, rightfront contact of relay I408, right back contact of relay I4I3, leftnormal contact of relay I4I9 to the winding of relay I401 and battery.Relay I401 operates, closing a circuit from grounded conductor I426,over the normal contact of test switch brush I002, conductor I031, frontcontact of relay I401, right back contact of relay 935 to.

the winding of relay I420 and battery. With relay I420 operated, thecircuit is ready to make thebusy test of the selected district junctor.

Busy test of district junctor In order not to interfere with serviceconnections, a test can only be started while the district junctor isidle, and the test circuit having selected a district junctor, firstmakes a test to determine whether that junctor is free.

